There are several methods to support multiple floors or a roof structure of a building, that is, by using a load bearing wall or by using a beam which is supported by posts on both sides of the beam. Should a wall require any windows a beam above the window and columns are installed on both sides of the window. A high-rise or larger type buildings, uses columns and beams to support the additional floors and roof loads above. On the other hand, smaller buildings also use walls to support the weight of additional floors or roof load above. These load bearing walls uses can be made of solid masonry, concrete or as a framed wall using wood or metal framing members typically spaced 16-24 inches apart. A non-load bearing wall can also be made using wood or metal framing members, the wall only supports itself not a roof or floor load above. The non-load bearing wall can also be built the same way, however the structural capacity of the framing members are less and therefore the material costs are less expensive.
The construction of a wall varies based on the type of materials that are used. For example a solid concrete or masonry wall does not need to be laterally supported, because the wall is connected horizontally from say one masonry block to another masonry block. On the other hand, a post and beam type construction needs to be horizontally braced somewhere within that building otherwise the building would collapse if the wind or an earthquake would cause the building to move horizontally. Usually that is done by adding diagonal braces that criss-cross between the columns or by adding a solid wall somewhere within the building structure. When a smaller wood or metal framed wall has a similar problem, that is, the framing members need to be supported between each other using by applying plywood over the framing members. The plywood acts a shear wall, by not allowing the framing members to fall down like “domino's”.
Typically the higher the wall, the thicker the wall becomes. This occurs because if a tall wall is not laterally supported (braced by another structure) then the wall will bend. For example, a masonry wall can have a pilaster added, that is, a column attached to the wall and made of the same material.
Typically wood or metal framed wall construction must be secured to a foundation or concrete slab either by anchor bolts embedded within a concrete wall and or attaching tie down supports which are secured to the metal or wood studs and then anchored into the foundation or foundation.
Concrete construction has changed over the years since the days of the Roman Empire where concrete was initially used. From the early concrete building structures, concrete wall construction has developed into today's construction uses ICF's (insulated concrete forms) to build concrete walls. Now as energy has become more expensive, these ICF's have reduced the amount of concrete within the wall by adding more insulation thereby creating columns and beams within the ICF's. These ICF's have a very rigid system with no flexibility on where to install the beams or columns.
Structural insulated panels or SIP's have a foam core with exterior skins usually plywood glued to the foam. Sometimes metal or wood is installed within the foam core and the wood or metal is connected between the panels for additional support. SIP's have a very limited load bearing capacity due to the structural limitation in the design of the panels. The use of SIP's have been limited to one or two story building and have never been used in conjunction with precast or poured-in-place concrete walls.
Rigid insulation boards have been installed on metal channels for years and more recently rigid insulation has been glued onto metal channels as a thermal barrier. Insulating blocks have embedded channels within insulation blocks also embedding the metal channels within the rigid insulation. Some insulated concrete forms (ICF's) have embedded plastic connectors within their rigid insulation blocks also separating the rigid foam from the plastic connectors. Structural insulating panels (SIP's) have no thermal break when wood or metal is added at the connections of adjacent panels. None of the systems has an interior and sheathing insulation combined as well as creating a thermal break within a wall forming structure.
Thin faced precast concrete wall panels have been using light gauge metal framing for the structural backing for a few years now. When the concrete is poured face up, insulation supports the concrete until it has cured, while pouring the concrete face down in a forming bed, the light gauge metal framing is suspended over the forming bed and the metal channel is typically embedded into the concrete facing and usually no thermal break is accomplished. These systems do not combine the wall and sheathing insulation, plus have that thermal break as well as the flexibility to install columns and beams within the structure.
Thin cementitious material has been applied over foam, however usually to make a block, and the entire block is entirely encased with the cementitious material. Sometimes a wall panel has also been fully encased with the cementitious material and recently an ICF block has been partially encased with the cementitious material. Cementitious materials have not applied to wall panels where the cementitious materials have had the thermal break between the interior and exterior surfaces.
Modular buildings have been very limited in their design and functionality of their superstructure. Modular construction has been typically limited to wood framed building and some have been developed using steel as a column and beam substructure. Concrete has had limited exposure in modular buildings, as well as the use of a structural insulating core to form concrete beams and columns within the exterior walls and common walls between modular buildings.
Today, more and more steel or concrete post and beam buildings are being built. Construction techniques for building walls have been changing significantly including metal channel framing and stay-in-place insulated forms where concrete is installed within these forms.